assimp/tools/assimp_view/Normals.cpp

/*
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Open Asset Import Library (assimp)
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*/

#include "assimp_view.h"

#include "PostProcessing/GenFaceNormalsProcess.h"
#include "PostProcessing/GenVertexNormalsProcess.h"
#include "PostProcessing/JoinVerticesProcess.h"
#include "PostProcessing/CalcTangentsProcess.h"
#include "PostProcessing/MakeVerboseFormat.h"

namespace AssimpView {

using namespace Assimp;

bool g_bWasFlipped = false;
float g_smoothAngle = 80.f;

//-------------------------------------------------------------------------------
// Flip all normal vectors
//-------------------------------------------------------------------------------
void AssetHelper::FlipNormalsInt() {
    // invert all normal vectors
    for (unsigned int i = 0; i < this->pcScene->mNumMeshes;++i) {
        aiMesh* pcMesh = this->pcScene->mMeshes[i];

        if (!pcMesh->mNormals) {
            continue;
        }

        for (unsigned int a = 0; a < pcMesh->mNumVertices;++a){
            pcMesh->mNormals[a] *= -1.0f;
        }
    }
}

//-------------------------------------------------------------------------------
void AssetHelper::FlipNormals() {
    FlipNormalsInt();

    // recreate native data
    DeleteAssetData(true);
    CreateAssetData();
    g_bWasFlipped = ! g_bWasFlipped;
}

//-------------------------------------------------------------------------------
// Set the normal set of the scene
//-------------------------------------------------------------------------------
void AssetHelper::SetNormalSet(unsigned int iSet) {
    // we need to build an unique set of vertices for this ...
    {
        MakeVerboseFormatProcess* pcProcess = new MakeVerboseFormatProcess();
        pcProcess->Execute(pcScene);
        delete pcProcess;

        for (unsigned int i = 0; i < pcScene->mNumMeshes;++i) {
            if (!apcMeshes[i]->pvOriginalNormals) {
                apcMeshes[i]->pvOriginalNormals = new aiVector3D[pcScene->mMeshes[i]->mNumVertices];
                memcpy( apcMeshes[i]->pvOriginalNormals,pcScene->mMeshes[i]->mNormals,
                    pcScene->mMeshes[i]->mNumVertices * sizeof(aiVector3D));
            }
            delete[] pcScene->mMeshes[i]->mNormals;
            pcScene->mMeshes[i]->mNormals = nullptr;
        }
    }

    // now we can start to calculate a new set of normals
    if (HARD == iSet) {
        GenFaceNormalsProcess* pcProcess = new GenFaceNormalsProcess();
        pcProcess->Execute(pcScene);
        FlipNormalsInt();
        delete pcProcess;
    } else if (SMOOTH == iSet) {
        GenVertexNormalsProcess* pcProcess = new GenVertexNormalsProcess();
        pcProcess->SetMaxSmoothAngle((float)AI_DEG_TO_RAD(g_smoothAngle));
        pcProcess->Execute(pcScene);
        FlipNormalsInt();
        delete pcProcess;
    } else if (ORIGINAL == iSet) {
        for (unsigned int i = 0; i < pcScene->mNumMeshes;++i) {
            if (apcMeshes[i]->pvOriginalNormals) {
                delete[] pcScene->mMeshes[i]->mNormals;
                pcScene->mMeshes[i]->mNormals = apcMeshes[i]->pvOriginalNormals;
                apcMeshes[i]->pvOriginalNormals = nullptr;
            }
        }
    }

    // recalculate tangents and bitangents
    Assimp::BaseProcess* pcProcess = new CalcTangentsProcess();
    pcProcess->Execute(pcScene);
    delete pcProcess;

    // join the mesh vertices again
    pcProcess = new JoinVerticesProcess();
    pcProcess->Execute(pcScene);
    delete pcProcess;

    iNormalSet = iSet;

    if (g_bWasFlipped) {
        // invert all normal vectors
        for (unsigned int i = 0; i < pcScene->mNumMeshes;++i) {
            aiMesh* pcMesh = pcScene->mMeshes[i];
            for (unsigned int a = 0; a < pcMesh->mNumVertices;++a) {
                pcMesh->mNormals[a] *= -1.0f;
            }
        }
    }

    // recreate native data
    DeleteAssetData(true);
    CreateAssetData();
}

}